"You say there is a horse in your bathroom, and all you can do is stand there naming Beatles songs?” asks my 15-year-old son, Zach.

The sun is beating down, and we’re sitting on the cement back steps of my dad’s rock house, a sprawling structure one mile off Highway 50 and 60 miles west of Austin in central Nevada. Zach reads to me from Dirk Gently’s Holistic Detective Agency by Douglas Adams. Adams, best known forThe Hitchhiker’s Guide to the Galaxy, dedicated this book to his mother who liked the science-fiction mystery for “the bit about the horse.”